Railway-traffic-controlling apparatus



June 29 1926,

S. M. LUCAS RAILWAY TRAFF IC CONTROLLING APPARATUS Filed August 2'7, 1923 J a F:

C S u 2/ L 4 Patented June 29, 1926.

UNITED STATES 1,5903% PATENT OFFICE.

SAMUEL M. LUCAS, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO THE UNION SWITCH & SIGNAL COMPANY, OF SWISSVALE, PENNSYLVANIA, A CORPORATION or PENNSYLVANIA.

RAIL\VAYTRAFFIC-CONTROLLING APFARATUS.

Application filed August 27, 1923. Serial No. 659,505.

My invention relates to railway tratfiocpxr trolling apparatus of the type comprlsmg train carried governing means controlled by energy in the trackway. More particularly my invention relates to the trackway portion of such apparatus.

I will describe one form of railway traflic controlling apparatus comprising my invention, and will then point out the novel features thereof in claims. v

The accompanying drawing is a diagrammatic view showing one form and arrangement of trackway apparatus embodying my invention.

Referring to this drawing, the reference characters 1 and 1 designate the track rails of a railway over which traffic normally moves in the direction indicated by the arrow. A track section AC is separated from the rest of the track by means of insulated joints '2, and this section is further divided into sub-sections for purposes which will appear hereinafter. As here shown section AC comprises a rear sub-section A--B and a forward sub-section BC, which subsections are separated by insulated joints 2 Means are provided for supplying the rails of each sub-section in parallel with a train governing current which I will term a loop current. For this purpose sub-section A-B is provided with an impedance 1 L 7 connected across the rails adjacent the entrance end of the sub-section and a similar impedance 15 connected across the rails adjacent the exit end of the sub-section. Two other similar impedances 16 and 17 are connected across the rails adjacent the entrance end and the exit end, respectively, of subsection B-C. The connections of the loop circuits are made to the mid points of these impedances.

Loop current is constantly supplied to sub-section AB by a loop transformer E, the circuit passing from the secondary 10 of transformer E, through wire 22, impedance 15, the rails of sub-section AB, impedance 14, and wire 23 back to transformer E. The primary 11 of transformer E is constantly supplied with alternating current from an alternator H, over line wires 5 and 5 The sub-section BC is at times supplied with loop current from a loop transformer D, the primary 9 of which is constantly supplied with alternating current from line wires 5 and 5 The loop circuit for subsection B-C passes from secondary 8 of loop transformer D, through wire 24, circuit controller F operated by a signal S wire 25, impedance 17, through both rails of sub-seotion BC in parallel, impedance 16, and wire 26 back to transformer D. The circuit just traced is closed only when signal S indicates caution or proceed, and at all. other times the supply of loop current to subsection BO is discontinued;

The purpose of the insulated joints 2 at point B is to preventthe flow of loop current from one sub-section to the other.

Track circuit current of one relativepolarity or the other is supplied'to the entire section AC from a track transformer T,

the primary 4: of which is constantly supplled wlth alternating current from line wires 5 and 5 Interposed between the sec ondary 3 of transformer T and the rails of section AC is a pole changer J controlled in anysuitable manner as by signal S Track circuit current is carried past the insulated joints 2 at point B by means of a bonding device K. As shown in the drawing device K comprises a core 18 of magnetiza-ble material such as laminated iron. This core is provided with a windmg 19 connected around joint 2 in rail hand a second winding 20 connected around joint 2 in rail 1 These windings are so arranged on the core 18 that the magnetic fields set up in this core by currents flowing in opposite directions in the two windings 19 and 20 at any instant tend to section B-C to subsection AB or vice it passes through versa through device K, windings 19 and 20 in the same direction and the impedance of the bonding device.

K is therefore comparatively high and hence is effective to choke back such currents. It is, therefore, plain that stray loop currents are prevented from passing from one subsection to the other.

The trackway apparatus herein shown and described is intended for co-operation with train carried governing mechanism so arranged that a less restrictive indication is received on the train whenboth track and loop currents are present in the. rails, and amore restrictive indication is received on the train when loop current is not, present in the rails. Obviously, then, if loop cur rent strays from one' sub-section into] another sub-section which is not supplied with loop current in the normal manner, a less restrictive indication willv be given when a more restrictive indication should be given. One feature of my invention is the prevention of such stray supply of loop current, without interfering with the free flow of track circuit current from sub-section to sub-section.

Although I- have herein shown. and de scribed only one form and: arrangement of railway traf'riccontrolling apparatus em.-

' bodying my invention, it is. understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.v I

IIaving thus described my invention, what I claim is:

1. Trackway apparatus for a train concuit current which flows through the track rails in series to one said sub .-secti-on,, and means for allowing the flow of trackcircuit current but not loop current from one sald sub-sect-ionto the other; I

3. In combination, a stretch of railway track divided into a forward and rear sub-section, means for constantly supplying loop current to said rear sub-section,j neans responsive totraflic conditions for supplying loop current to said forward subrsection,

means for supplying track circuit, current to said forward subsection, and" means for conducting said track circuit current but not loop current from said forward section to said rear section.

4. In combination, a stretch of railway track divided by means of insulated joints into a. forward and a rear sub-section, means for supplying each sub-section separately with current which flows in the same direction in the two track rails, means for supplying an electromotive force across the rails of-said forward sub-section, and a bonding device adjacent the junction. of, said two sub-sections for permitting current flowingin opposite directions. in. the two rails but not current flowing in. the same direction in the two track rails, to pass from. one sub-section to the other.

5. In combination, a stretch of railway track divided by means of insulated joints intoa forwardand, a rear sub-section, means for supplying each sub-section separately with current which flows in the same direction in the two track rails, means for supplying a-n electromotive' force across. the rails of said forward sub-section, and a bonding device adjacent the junction of said two sub-sections; and comprising a magnetizable core, a first winding. on said core connected around the insulated joint in one rail, and a second winding on said core connected around the insulated joint in. the other rail, the-two windings being so disposed that the. magnetic fields set up by our rents flowing in opposite directions in the two windings at any instant tend to neutralize each other. i

6. Trackway apparatus for a train controlling system comprisinga section of track divided intosub-sections insulated from each other, means for supplyingeach sub section separately with loop current which flows through the track rails in multiple, and means for supplying the sub-sections in. series with track circuit current which flows through the track rails in series.

In testimony whereof I atfix my signal.-

ture. V

' SAMUEL. M. were. 

